Acquire

Though not as fantastic as Bribery, the artifact version can still deliver. Though sometimes you’ll have to settle for a Solemn Simulacrum or (Sensei’s Divining Top), you just might get lucky and net a Duplicant or Sword of Light and Shadow. Unlike Bribery where the card you’re taking from them is likely to worth more than the 5 Bribery costs, with Acquire you’re more likely to net a card that costs less than 5 but impacts the board a good deal more.

AEther Mutation

Bouncing a big guy from the other side of the board can sometimes “Time Walk” your opponent, and getting a small army at the same time is huge. I think of this as a mini Martial Coup. Even better if you have something to do with the tokens.

AEther Storm

A control deck doesn’t play this to deal 4 damage for 4 mana, but as a kind of mind game to dictate the flow of the game. Like with Standstill, players will often wait too long before breaking it, and time is almost always on the control player’s side.

All Suns' Dawn

A favorite in EDH, this will seldom “draw” you all 5 cards in a two player game, but it can be very frustrating to an opponent when the same cards they saw fit to spend removal on return to your hand. I would go as low as playing this in a 3-color deck, as regrowing 3 cards for 5 mana is still awfully good.

Ana Sanctuary

Animal Magnetism

Best with (Sensei’s Divining Top) in a creature-heavy deck, this could make for one of those quick Turn 5 Eldrazi concessions. Works well with cards that make use of the graveyard.

Annihilate

Card advantage at instant speed. When’s this one getting reprinted?

Auratouched Mage

Including an Eldrazi Conscription in your deck makes this a back-breaking one-card combo. Ouch. This kind of “oops I win” combo fits into any deck that plays white.

Barrin's Spite

The fact that your opponent gets the Sophie’s Choice hurt this, but it still sets them back by their two best creatures.

Cabal Slaver

Game over in a dedicated goblin deck.

Call of the Wild

Callous Oppressor

The built-in disadvantage here is mitigated by the format’s deck size and singleton nature. They’re likely just going to name the creature type of their favorite card on board or in hand, letting you enslave virtually everything else they’ve got. Anyone else remember fearing this guy in Standard, before Vedalken Shackles obsolesced him?

Candles of Leng

Unoriginal tech in singleton formats, but still a great deal if you’re heading into a long game.

Captain's Maneuver

Save your guy and kill theirs for pure card advantage, or aim it back at their head.

Cauldron Dance

It requires perfect timing, but with creatures with good Enters the Battlefield abilities this can turn a game around.

Caustic Tar

A surprisingly fast clock that shines in an environment where creature removal is far more common than land destruction or enchantment kill.

Ceta Sanctuary

How huge is drawing an extra couple of cards every turn? Play with Firewild Borderpost.

Choice of Damnations

Just a beating in the late game, when they’re either going to lose half their life or half their permanents. Your choice. I’ve played this a grand total of once, years ago, and my opponent didn’t read the card – they picked “zero” and somehow I pulled out the win.

Colfenor's Plans

See, you’re also playing a color with enchantment kill, and you just drew seven cards. The Arcane Laboratory drawback elegantly neutralizes a good deal of the card’s benefit, but not if you’re playing instants on your opponent’s turn. Assuming you’re also playing lands you drew from the (Colfenor’s Plans), you’ll ideally be playing three cards a turn, so you’ll be done with it and ready send it packing very quickly.

Conquer

Annex 2. Useful in a format with many powerful lands. Accelerate yourself and set them back.

Consecrate Land

Changes to the templating of this card make the enchanted land indestructible, which could be interesting in a deck with lots of manlands.

Darksteel Garrison

Speaking of… It’s a little silly, but put this on a manland and it becomes very hard to kill. And it pumps itself when it attacks. The Garrison won’t even fall off at end of turn. And since “Fortify” didn’t come back during “land matters” Zendikar block, it’s looking like this is the only chance you’ll have to use this strange ability.

Dauthi Embrace

Shadow is almost always the same thing as unblockable. And since all it takes is 2 mana it’s easy to give to multiple creatures, or your entire team. Expect this to end games quickly.

Death Mutation

It’s expensive, but how do you lose afterword?

Dimensional Breach

Win-more, so long as you have the biggest threat on the board when you cast it. Unless you’ve got Ghostway or Flickerwisp. Oh, and 10 mana. This is one of the biggest effects I’ve seen on a card outside of Scheherazade.

Dreams of the Dead

Dregs of Sorrow

It costs a lot, but it’s also a one-sided Decree of Pain. Or a super-cantripping Plague Wind.

Eater of Days

Hey, it’s the Casual Room, and sometimes you’ve just got to go for it. Don’t you ever play cards just for the story potential?

Echo Chamber

Who doesn’t love a little bit of Kiki-Jiki action now and again? And that “opponent’s choice” bit doesn’t mean you have to leave them with a choice they’re happy with: pick on their little, uninteresting guys like a schoolyard bully to guarantee you’ll end up with one of their best creatures.

Elemental Augury

Sure, you can use it as an overpriced Top that doesn’t draw, but wouldn’t you rather decide which card your opponent is going to draw every turn?

Endless Whispers

A Casual Room classic. It’s difficult to build 100CS decks around effects like this, but it’s much easier to play around it if you happen to draw it.

Enshrined Memories

Green doesn’t get a lot of card drawing outside of Harmonize and the de facto card drawing of mana acceleration and this is a great mid/late game way to restuff your hand with dudes.

Evangelize

Without the kicker you have to sculpt the game state for this to shine, but later in the game you’ll be stealing guys almost as fast as they can cast them.

Feast or Famine

Sometimes choice is a kind of pseudo card advantage: right up until you cast it, Feast or Famine is like having both Terror and Ashcoat Bear in your hand. It’s Schrodinger’s Card. You’ll almost always use this as a Terror, but sometimes you’ll need another creature to attack a Planeswalker, for example.

Fervent Charge

There are lots of cards with this effect as a one-of instant or sorcery, but this cousin of Fires of Yavimaya will put your opponent on the defensive the entire rest of the game.

Here’s how I tend to look at cards with (Regrowth) effects: if it’s in your graveyard it was either good enough to cast once already or good enough for your opponent to kill. Help yourself out here by targeting yourself with (Relic of Pregenitus).

Form of the Dragon

You have to play this at least once in your life. It’s 8 cents. Come on. Are you trying to tell me you don’t want to become a DRAGON? Then go back in time and tell your 9 year old self that you refused to shell out 8 cents to turn into A DRAGON. When you’re done, try my awesome variant: Form of Mogg Fanatic.

Gather Specimens

Godo, Bandit Warlord

Not all that janky, this one costs a surprisingly cheap 10 cents. For 6 mana it fetches AND plays your Sword of Light and Shadow. I’ve found it best to play more than just one powerful equipment card in your deck to go with Godo, like a Loxodon Warhammer, in case you draw one before you draw Godo. His untapping/second combat ability doesn’t just work with Samurai – it’s also great with Vigilance creatures.

Golden Wish

Due to certain MTGO-only rules constraints you’re only able to access your sideboard with the wishes in timed games. But since the Casual Room defaults to single games instead of 2 of 3, why not create a silver bullet sideboard for your 100CS deck that you’ll only use when wishing? Golden Wish costs a very friendly 12 cents, and can tutor up the exact artifact or enchantment you need at any given time. With access to Cunning Wish, Living Wish, or Burning Wish (the ones that saw tournament play) you can do the same thing with other card types, and they’re only a few dollars each. The strategy is still a sound one.

Grim Reminder

Still not exactly playable, but there’s enough overlay with some popular cards that you’re bound to hit something sooner or later.

Grinning Totem

Bribery effects are quite powerful in 100CS decks since the top end of mana curves tend to be swingy bombs. Stealing one of their best cards has the added benefit of making sure they never draw it. Grinning Totem is extremely flexible, even allowing you to steal utility lands like Academy Ruins and (Volrath’s Stronghold) if your board position is suited for it.

Guardian Idol

Why not play the signet that’s also a “manland”? It certainly doesn’t attract as much heat as something like Phyrexian Totem.

Hecatomb

I see this as a mono-black Fireball that lets you kill over multiple turns. Kill their team first then finish them off at your leisure.

Hesitation

Not quite Standstill…

Hibernation's End

Another popular Casual Room card, this one makes subtle but important demands of your deckbuilding. For maximum value it’s important that you actually have early drops that make this card worthwhile, especially since Hibernation's End attracts a lot of hate and may not last long. Thankfully we now have excellent one-drop threats like Dragonmaster Outcast and Scute Mob, so you’re not stuck fishing for your Llanowar Elves every time.

Hobble

Cheap, cantripping removal. Just make sure you don’t accidentally attack into their Eldrazi with it. This is perhaps my favorite card of all time. Since it costs a big ol’ 2 cents, you should probably shell out for the playset and use them in Pauper too.

Hymn of Rebirth

Your graveyard or theirs.

Immortal Coil

This strikes me as the easiest Lich effect to build around since you don’t lose the game if the Coil is removed. It also doesn’t cause you to skip your draw step, which is nice.

Invincible Hymn

Beacon of Immortality is great in EDH where you start with 40 life, but Invincible Hymn is much better in 100CS where you’re likely to go up to 60 or so life.